Aortic Dissection Diagnosis
Aortic dissection is difficult to diagnose because symptoms often are similar to those caused by other conditions. Diagnosis often involves taking a medical history (if possible) and performing a physical examination and imaging tests.
During the physical exam, the physician takes blood pressure and notes any differences in pressure between the right and left arms or between the arms and the legs. Other signs of aortic dissection include abnormally low blood pressure readings, which can indicate shock or heart attack, and enlarged veins. The physician also uses a stethoscope to listen for unusual sounds (e.g., a "blowing" murmur) coming from the chest or abdomen.
In most cases, bloods tests are not used to diagnose aortic dissectionthe time involved in drawing and analyzing blood is not practical in this emergency situation. However, if blood tests are taken, they can help the physician determine where the dissection is causing the most damage.
For example, high levels of certain substances in the blood (e.g., creatinine, blood urea nitrogen) indicate problems in the arteries that supply the kidneys (renal arteries). High levels of tropomin and creatine kinase are signs of reduced blood supply to the muscles of the heart wall (called myocardial ischemia). Decreased blood levels of hemoglobin (iron-containing substance in red blood cells) (may want to explain what hemoglobin is) and hematocrit (volume of mature red blood cells) (ditto for hematocrit) indicate that the dissection is probably leaking or has ruptured.
Imaging Tests to Diagnose Aortic Dissection
Imaging tests are critical to diagnose aortic dissection. The most common tests include the following:
- Chest x-ray (used to determine if blood has entered the lungs)
- CT scan of the chest (x-rays are taken from many different angles to create cross-sectional images; a contrast solution [iodine-based dye] may be used to improve images of the heart, aorta, and surrounding tissue)
- Magnetic resonance angiogram (MRA; uses a magnetic field and radio waves to create images of blood vessels)
- Transesophageal echo (TEE; type of ultrasound that uses sound waves emitted from a probe inserted into the esophagus through the mouth to create detailed images of the heart and aorta)
- Echocardiogram (cardiac echo; ultrasound procedure used to determine how well the heart is functioning and if any abnormalities are present)